Filters for removing impurities from a fluid flow are well known and are used in many applications. For example, filters are used to remove particles and bacteria from water to purify the water, thus making it suitable for drinking. Filters are also used to strain particulate from flows of other fluids, such as motor oil and milk. One example of a filter used to purify drinking water is shown in the Higashijima et al. patent, U.S. Pat. No. 5,397,462. The Higashijima et al. patent discloses a vertical water filter having a replaceable cartridge that removes impurities from a water supply. The filter is attached to a flow of water, which is forced vertically up into the cartridge and through a filter member. The water exits the filter at its top portion as a purified water supply suitable for drinking.
Another example of a water filter is shown in the Winans patent, U.S. Pat. No. 1,532,013. The Winans patent discloses a device for filtering rain water. The device has a wire screen positioned over a basket that contains a filtering material, such as charcoal. Rain water flows into the screen and the charcoal under normal gravitational forces. The screen removes large particles from the water flow, and the charcoal removes additional, smaller impurities from the rain water. The water then exits the bottom of the basket as a filtered water source.
Chemicals, such as fertilizers and weed killers, are in widespread use to promote the growth of crops and grass. Through normal ground water run off, these chemicals can seep into the subterranean water table. This problem is particularly evident in situations where a wide variety of chemicals are used to maintain a tract of land, such as at a golf course. Golf course groundskeepers typically use different types of fertilizers and weed killers to promote and maintain the health of fairways and greens. Because proper drainage is required to keep the course in shape for golfers, a tile system is often used to drain ground water from fairways and greens. The chemicals applied to the course, however, are also carried away by the ground water.
To prevent these chemicals from seeping into the subterranean water table, a filter can be used to remove the chemicals prior to discharging the excess ground water from the tile drain. These filters can be horizontal in nature, with fluid draining into and collecting at the filter under normal gravitational forces. Pressure from the water that collects at the filter forces the water through the filter. One shortcoming of filters of this type is that they typically only use a single filter element, which is thus capable of removing only a predetermined number and type of chemicals or impurities from the water supply. In addition, conventional horizontal filters make inefficient use of the filter element since the water flows primarily through the bottom half of the filter. As such, the bottom half of the filter element becomes clogged with impurities, thus necessitating replacement of the filter element, while the top half is still useable.
There is therefore a continuing need for an improved filter system. In particular, a filter system that creates and promotes a uniform horizontal fluid flow through a filter element is desirable to make more efficient use of the filter element. In addition, a filter system that permits more than one filter element to be used to remove a greater number of chemicals and impurities from a water supply is desirable. A filter system having removable filter elements is also highly desirable to permit the easy replacement of the filter elements after they become clogged with impurities.